Composition for use in a dishwasher

ABSTRACT

The invention relates to a composition for use in a dishwasher which is provided in the form of a tablet. The inventive composition is characterized by a base composition which essentially carries out its function during the main cleaning cycle of the dishwasher, and is also characterized by at least one particle. Said particle has at least one core that comprises at least one substance which essentially carries out its function during the rinse cycle of the dishwasher. The particle also has a coating which, for the most part, completely surrounds the core(s). Said coating comprises at least one compound whose solubility increases with a declining concentration of a specific ion in the surrounding medium. The at least one particle is arranged in or on the tablet in such a way that the surface of the particle(s) is, at most, partially in direct contact with the surface of the base composition surrounding this/these particles. In order to prevent the coating from substantially dissolving or to prevent the coating from substantially detaching from the core(s), the concentration of the specific ion in the local surrounding of the particle(s) is sufficiently high until the tablet has, for the most part, completely dissolved. The invention also relates to a method for conducting a dishwashing cycle in a dishwasher while using the inventive composition.

The present invention relates to a composition for use in a dishwashingmachine and a process for the use thereof.

Although modern dishwashing machines in most cases have numerousdifferent washing programs, which differ with regards to the durationand temperature of the individual washing cycles, all washing programsessentially consist of the following basic steps: preliminary washingcycle, main cleaning cycle, one or more intermediate rinsing cycles, aclear rinsing cycle and drying. Whereas the machine dishwashing agentfor bringing about the cleaning action is added at the start of the maincleaning cycle, during the clear rinsing cycle special agents are used,e.g. clear rinsing agents. Clear rinsing agents are intended to ensurethat when washing with water water droplets are not left behind on thewashed articles which, after drying on, leave behind marks of substancesdissolved/dispersed in the droplets.

These two functionalities, namely the cleaning action of the machinedishwashing agent and the described function of a clear rinsing agent,have hitherto been brought about using two separate charging or dosingdevices and products charged or dosed at different points during thedishwashing cycle.

Apart from the use of clear rinsing agents, there is still a need forfurther substances evolving their activity during the washing or rinsingcycle, such as e.g. an antibacterial activity (e.g. cationic compoundsor triclosan), silver protection agents (e.g. benzotriazole), an odorousaction (fragrances, perfume), bleaching action/disinfection (chlorinebleaches), odour masking (e.g. polyvinylpyrrolidone), anti-coatingagents and enzymes for additional purposes (e.g. lipase for removinggrease and fat deposits in the dishwasher). However, modern dishwashershave no suitable charging systems for this purpose.

The aim of the present invention was consequently to combine in a singlefunction the cleaning function and the function or functions of thesubstance or substances to be added during the clear rinsing cycle witha constant efficiency compared with the results obtainable with aseparate charging or to permit the charging of substances other than theclear rinsing agent in the clear rinsing cycle.

DE-OS 20 65 153 and 20 07 413 disclose detergent blanks for use asdetergents, in which it is inter alia provided that two componentshaving a different functionality are combined. The structure comprisesan enveloping shell, which is e.g. formed from two shell halvescomprising a cleaning agent, as well as a cavity enclosed by the shellsand which contains additives such as softeners, brighteners, etc.

British patent 1 390 503 discloses a liquid detergent containingcapsules, which are insoluble in the composition, but release theircontent if the composition is diluted with water. This objective isachieved in that the capsules are coated with a substance having a poorsolubility in water solutions with high ionic strength, but becomingsoluble if the ionic strength is reduced by dilution. It is pointed outthat this procedure can be used to incorporate materials in the liquidcleaning agent, which are unstable in the latter or would produce aninstability if added directly. It is also proposed that this procedurebe used in order to delay the release of a specific substance. Referenceis made to use in machine dishwashing agents and it is proposed for theencapsulation of tribromosalicylanilide in order to stabilize thelatter. The encapsulated material is released within two minutesfollowing the dilution of the cleaning agent with water, i.e. in themain cleaning cycle.

U.S. Pat. No. 4,082,678 describes a fabric conditioning productcomprising a closed container containing a releasable agent, which isused to make water-insoluble or non-dispersible an inner containerlocated in the container and which is normally water-soluble orwater-dispersible, the inner container containing a fabric conditioner.The inner container is made from a substance, whose solubility in wateris highly dependent on the ionic strength or the pH-value of the mediumand the agent used for rendering the inner container insoluble is anagent for controlling the pH-value or ionic strength.

Japanese patent applications KOKAI 60-141705, 61-28440, 61-28441,61-28596, 61-28597 and 61-28598 describe processes for the production ofpH-sensitive microcapsules for use in detergents. The pH-sensitivecoating is a copolymer of the following monomers:

A) at least one basic monomer of formula I:

 in which R is hydrogen or a methyl group, R¹ and R² in each case analkyl group with 1 to 3 carbon atoms and x an integer from 1 to 4,

B) at least one monomer, which is insoluble or difficultly soluble inwater and

C) at least one water-soluble monomer.

It is stated that the polymers described are insoluble at a pH-value of9.5 or higher and are soluble at a pH-value of 8.5 or lower. Adescription is given of different ingredients of cleaning agentcompositions, which can be successfully and usefully coated with thepolymers described. The aim of the invention described therein is thatthe substances only evolve their function during the rinsing cycle,protect the same up to the start thereof and then immediately releaseit. The use for dishwashing machines is not described.

A disadvantage of the solution described in these Japanese patentapplications is that the enveloped particles are in direct contact withnon-alkaline washing water at the start of the washing cycle which canlead to a partial dissolving of the protective envelope.

Japanese patent KOKAI 50-77406 discloses a washing aid surrounded by awater-soluble envelope obtained by mixing polyvinyl acetal dialkylaminoacetate and at least one organic acid, which is solid at ambienttemperature. This protective envelope serves to protect the washing aidduring the main washing cycle and release it during rinsing cycles. Thedescribed compound reacts to a change of the pH-value between the mainwashing cycle and the rinsing cycle. The correspondingly envelopedparticles are mixed with conventional pulverulent detergent. Here againthe disadvantage of a possible partial dissolving of the protectiveenvelope at the start of the washing cycle occurs.

European patent applications EP 284 191 A2 and 284 334 A2 disclose awater-soluble polymer film for the release of washing additives in therinsing cycle of washing machines which, during the normal washingcycle, remains intact over a typical temperature range and rapidlydissolves in the rinsing cycle. It is pointed out that although the useof pH-sensitive coatings is known, said films are normallytemperature-sensitive, so that they are not reliably stable during thedifferent temperatures occurring in the washing cycle. The solutionproposed is a pH-dependent material (which undesirably also has apositive temperature-dependent dissolving behaviour), which is combinedwith a material having a negative temperature-dependent dissolvingbehaviour. This combination is intended to guarantee that the coatingsdo not dissolve at the high temperatures at the start of the washingcycle (particularly the very high temperatures occurring in Americanmachines). No reference is made to a use for machine dishwashing agents.

European patent application EP 481 547 A1 discloses multilayer machinedishwashing agent tablets with a core, a separating layer surroundingthe core and an outer layer for the sequential release of theingredients of the different layers. The aim of this tablet is to solvetwo different problems, namely 1) incompatible materials can beformulated together in a single tablet and released at different timesin order to prevent mutual influencing and 2) compositions intended toevolve their functions at different times can be formulated in a singletablet.

One of the disadvantages of the prior art described in this document isthat the only production process described is the successive moulding ofthe individual components. This leads to a risk of the core and/or coreenvelope being deformed, which can cause damage (and therefore areduction of the protective action) of the core envelope and also (as afunction of the core composition) can bring about a “bleeding”, of thecore into the envelope material and basic composition. In addition, theintimate, full-surface contact between the individual layers can lead toundesired reactions occurring in the boundary layers, particularlybetween the envelope and the basic composition.

The second essential disadvantage of this prior art is that forinitiating dissolving of the enveloping layer the temperature and inparticular the contact time with the washing solution is used as thetriggering factor, i.e. temperature-sensitive materials are used for theenvelope material. As the temperature/time gradient in dishwashingmachines can vary widely as a function of the program chosen, it isdifficult, if not impossible, to select a material for the envelopeusable for all possible programs of modern dishwashing machines. EP 481547 A1 (p 7, lines 37 to 43) admits that the choice of the material forthe enveloping layer must take account of equipment and program-specificfeatures. Therefore the practical usability of the products described isclearly limited.

PCT application WO 95/29982 discloses a machine dishwashing agent with adelayed release of a clear rinsing agent in the form of a nonionicsurfactant, which together with an inorganic builder salt forms a coreparticle, which is provided with a wax-like envelope in order to ensurethe desired release. This envelope is a substance which does not melt atthe operating temperatures encountered during the cleaning cycle, butchemically disintegrates under alkaline pH-values in a gradual manner sothat there is still an effective clear rinsing agent quantity at the endof the main cleaning cycle and is transferred into the clear rinsingcycle.

It is disadvantageous that the envelope is rendered soluble by chemicalsaponification at alkaline pH-values, so that the time when the clearrinsing agent substance is released from the core is a function both ofthe temperature and the length of the main cleaning cycle. The patentapplication contains no teaching as to how a product is to be formulatedwith which the clear rinsing agent is released in the clear rinsingcycle in all washing programs of any equipment type. In addition, thecore ingredient active as the clear rinsing agent is a nonionicsurfactant, which is absorbed on an inorganic builder salt. This givesrise to inferior clear rinsing results, particularly mark and spotformation on glass. Finally the product is a mixture of a granularcleaning agent and granular clear rinsing agent particles.

In view of the prior art described, the problem of the present inventionis to create a composition usable for most washing/rinsing programs ofdifferent dishwashing machine types and in each of these cases thesubstance or substances evolve their action essentially in the clearrinsing cycle, but are released at the earliest at the start of theclear rinsing cycle. The aim is to achieve this without significantrestriction to the choice with respect to the cleaning agent chosen, thesubstance or substances used for the clear rinsing cycle and otheringredients of the composition.

According to the invention this problem is solved with a compositioncharacterized by a basic composition, which evolves its function mainlyin the main cleaning cycle of the dishwashing machine and which is inthe form of a tablet, as well as at least one particle with at least onecore incorporating at least one substance, which evolves its functionessentially in the clear rinsing cycle of the dishwashing machine, andan envelope substantially completely surrounded by the core or cores,which incorporates at least one compound, whose solubility increaseswith decreasing concentration of a specific ion in the surroundingmedium. The at least one particle is so arranged in or on the tabletthat the surface of the particle or particles are at the most in partialdirect contact with the surface of the basic composition surrounding thesame and the concentration of the specific ion in the local environmentof the particle or particles is sufficiently high up to a substantiallycomplete dissolving of the tablet in order to prevent a significantdissolving of the envelope or a significant detachment of the envelopefrom the core or cores.

Preferably the or all particles are received in at least one tabletcavity completely surrounded by the basic composition and which has alarger volume than the or all the particles received in the particularcavity.

In an alternative, the particle or particles can be loosely arranged inthe interior of the cavity or, in another alternative, can be fixed. Inthe case of fixing in the interior of the cavity this preferably takesplace by an adhesive.

In a particularly preferred embodiment of the invention the cavity isarranged substantially centrally in the tablet interior.

According to the invention the tablet has a single, substantiallyspherical cavity, in which is received a single, substantially sphericalparticle, whose external diameter is smaller than the internal diameterof the cavity.

In an alternative embodiment of the invention the particle or all theparticles are received in at least one tablet cavity only partlysurrounded by the basic composition.

The cavity is preferably a depression in one of the tablet surfaces inwhich the particle or particles are at least partly received.

The particle or particles are preferably received in the cavity ordepression in such a way that they do not project over the tabletsurface or surfaces.

According to an embodiment of the invention the cavity or depression,parallel to one of the surfaces to which it opens or in which it islocated, has a substantially circular cross-sectional surface.

According to a special embodiment of the invention the cavity ordepression only opens towards the surface or surfaces to the extent thatthe particle or particles received therein cannot pass through theopening or openings of the cavity or depression.

Preferably the particle or particles are arranged in the cavity ordepression in loose form.

However, it is also possible for the particle or particles to be fixedin the cavity or depression, said fixing preferably taking place with anadhesive.

Preferably, according to the invention, the basic compositionincorporates at least one composition selected from the group comprisinga machine dishwashing composition, a water softener composition and awashing intensifier composition.

Preferably, according to the invention, the envelope incorporates atleast one compound which is not or only slightly soluble at theconcentration of the specific ion at the end of the main cleaning cycleof the dishwashing machine and in which the concentration of thespecific ion in the clear rinsing cycle has an adequate solubility suchthat it is so substantially dissolved or detached from the core or coresin the clear rinsing cycle that an at least partial escape of the corematerial into the clear rinsing cycle medium is rendered possible.

Preferably the solubility of the compound increases with decreasing OH⁻ionic concentration and therefore decreasing pH-value in the surroundingmedium.

According to a particularly preferred embodiment of the invention, thecompound has no or only a limited solubility at a pH-value above 10 andat a pH-value below 9 has an adequate solubility so that in the clearrinsing cycle it is substantially dissolved or detached from the core orcores in such a way that there is an at least partial escape of the corematerial into the clear rinsing cycle medium.

Said compound preferably incorporates a polymer and in particularlypreferred manner a pH-sensitive polymer, which has at least one repeatunit, which has at least one basic function, which is not part of thepolymer backbone chain.

In a preferred embodiment the polymer has at least one repeat unit basedon a compound selected from the group comprising vinyl alcoholderivatives, acrylates or alkyl acrylates, having said basic function.

In a special embodiment of the invention the polymer is a carbohydratefunctionalized with said basic function.

The aforementioned basic function is preferably an amine, preferably asecondary or tertiary amine.

In an alternative the repeat unit is based on a compound with thefollowing formula III:

in which G is a linking group chosen from —COO—, —OCO—, —CONH—, —NHCO—,—NHCONH—, —NHCOO—, —OCONH— or —OCOO—, R₁ independently of one another ishydrogen or an alkyl group with 1 to 3 carbon atoms, R₂, independentlyof one another, hydrogen or an alkyl group with 1 to 5 carbon atoms andx an integer from 1 to 6.

The repeat unit is preferably based on a compound with the followingformula IV:

in which R₁, independently of one another, is hydrogen or an alkyl groupwith 1 to 3 carbon atoms, R₂, independently of one another, hydrogen oran alkyl group with 1 to 5 carbon atoms and x an integer from 1 to 6.

According to another embodiment of the invention the basic function isan imine or a basic aromatic N-containing group, preferably a pyridinegroup or an imidazole group.

In a further embodiment the pH-sensitive polymer is derived fromchitosan.

The invention finally proposes that the compound incorporatesK-carrageenan.

According to an embodiment of the invention the core or cores compriseat least one material chosen from the group consisting of surfactants,antibacterial compositions, silver protection agents, fragrances,bleaches, disinfectants, odour masking agents, anti-coating agents andenzymes.

In an alternative the core or at least part of the cores can be in theform of encapsulated liquid, e.g. in the form of a liquid contained in agelatin capsule.

In an alternative embodiment the core or at least part of the cores isin solid form and preferably has a melting point of more than 35° C.,particularly preferred temperatures being 55 to 70° C.

The invention also relates to a process for performing a dishwashingcycle in a dishwashing machine, where the composition according to theinvention is added at an appropriate time during the preliminary washingcycle or the main cleaning cycle to the medium present in thedishwashing machine.

In a special embodiment of this process, for the case that the basiccomposition in the form of a tablet is unable following its dissolvingin the medium to make available up to the end of the main cleaning cyclea concentration of the specific ion in the medium which is sufficientlyhigh to prevent a significant dissolving of the envelope and asignificant detachment of the envelope from the core or cores, saidadequate concentration of the specific ion is provided by the additionof a further composition, such as e.g. a machine dishwashing agentcomposition, to the medium of the main cleaning cycle at an appropriatetime.

The composition according to the invention is characterized in that itgives excellent results both in the main cleaning cycle and in the clearrinsing cycle of a dishwashing machine. The tablet is dissolved duringthe main cleaning cycle and can evolve its corresponding, intendedaction (cleaning, water softening, washing intensifying, etc.). Theparticle located in or on the tablet contains as the core material thesubstance or substances intended to evolve their main function in theclear rinsing cycle of the dishwashing machine, e.g. clear rinsingagents.

Said substance or substances are protected by an envelope, which isstable at the ionic concentration, e.g. the pH-value and the temperatureof the main cleaning cycle and which do not or do not significantlydissolve or separate. Only if the ionic concentration or pH-value dropssignificantly by dilution, i.e. at the start of the clear rinsing cycle,is the solubility of the enveloping material reduced to such an extentthat it rapidly dissolves or separates and releases the active corematerial into the surrounding medium.

If special dosing or charging aids are not provided for dosing orcharging purposes and which can retain the particles according to theinvention, said particles are to be chosen sufficiently large that theyare not discharged to a significant extent during the pumping out afterthe main cleaning cycle and the intermediate rinsing cycle or cyclesfrom the dishwashing machine.

For the solution according to the invention it is essential that theparticle surface is at the most only in partial direct contact with thesurface of the basic composition of the tablet surrounding it. This cantake place in manner specifically described in this application, butalso in any other way achieving the aim in question. Examples are theloose arrangement of a smaller particle in a larger cavity and thefixing of a smaller particle in a larger cavity in such a way that thereis no or only a partial contact between the particle and the basiccomposition of the tablet, etc.

Compared with the prior art this procedure offers the advantage thatduring the production process, e.g. the moulding of the individualingredients occurring in successive steps, a deformation and possibly atherefrom resulting damage to the core or cores and/or envelope isreliably avoided, because it could give rise to a reduction of theprotective action of the core envelope. Through avoiding pressure beingexerted on the particle during any phase of the production process, itis also possible to ensure that for a specific core composition there isno “bleeding” thereof into the material of the envelope and the basiccomposition. In addition, for specific core compositions or the basecomposition it can be advantageous to avoid an intimate, full surfacecontact, because otherwise undesired reactions could occur in theboundary layers.

The term “local environment”, as used in the context of the particleaccording to the invention, is intended to designate the directenvironment around said particle. The ionic concentration in this localenvironment of the particle is the determinative factor for itsstability. In the case of the products according to the invention theionic concentration in said local environment, at least up to asubstantially complete dissolving of the tablet, is determined by ionsdissolving therein. Preferably the origin of the “specific ion” is, atleast in the initial phase of the main cleaning cycle, a compound fromthe tablet-forming basic composition or is produced by it in thesurrounding medium. In the most typical case for conventional basicdishwashing agents it consists of OH⁻ ions, whose concentration can beexpressed as a pH-value.

If the basic composition is not constituted by an e.g. basic machinedishwashing agent composition, but instead e.g. a water softenercomposition or washing intensifier composition, the protection of theparticle envelope by a sufficiently high ionic concentration in thelocal environment of the particle is possibly only ensured until thetablet has completely dissolved, namely in cases where the basiccomposition of the tablet is unable to provide a sufficiently high ionicconcentration in the medium. In these cases the sufficiently high ionicconcentration in the medium (and therefore also in the local environmentof the particle or particles) is brought about by dissolving the machinedishwashing agent (or a further specific additive).

The invention is now described in greater detail by means of thefollowing examples and drawings, wherein show:

FIG. 1 A typical pH-profile of a dishwashing machine.

FIG. 2 A first embodiment of the inventive composition in cross-section.

FIG. 3 A second embodiment of the inventive composition incross-section.

FIG. 4 A third embodiment of the inventive composition in cross-section.

FIGS. 5a & b A fourth embodiment of the inventive composition incross-section and plan view.

FIG. 6 A fifth embodiment of the inventive composition in cross-section.

The ionic concentration or pH-profiles of the cleaning or rinsing mediumin a dishwashing machine are dependent on the ingredients of thecleaning or rinsing agent used. A typical pH-profile when using aconventional basic machine dishwashing agent, e.g. CALGONIT® can begathered from FIG. 1 (dishwasher used BOSCH model SMS 3047).

The vertical broken line subdivision gives the duration of the followingstages: prerinsing, main cleaning, intermediate rinsing, clear rinsing.It is clear that the pH-value during most of the main cleaning cycle isin the range 10.0 to 10.5. The pH-value drops after the pumping out ofthe washing liquor at the end of the main cleaning cycle and the inflowof fresh water to a value of 9.0 during intermediate rinsing and tobetween 8.5 and 9.0 during clear rinsing.

FIGS. 2 to 6 show possible embodiments of the composition according tothe invention.

FIG. 2 shows a tablet comprising two half-tablets 2 and 3, which havethe same or different composition. For example as a basis use can bemade of commercially marketed two-layer tablets, in which the two layersconventionally have a different composition and are differentlycoloured. In the two half-tablets is roughly centrally provided anapproximately hemispherical recess 4 or 5 which, when the tablet 1 isjoined together, leads to a roughly spherical cavity.

In the embodiment shown in said cavity is placed a single particle 6comprising the core 8 and the pH or ionic concentration-sensitiveenvelope 9, whose external diameter is slightly smaller than theinternal diameter of the cavity in the tablet. Both in the embodimentshown in which the particle is loosely received in the cavity and in anembodiment where it is fixed by an adhesive applied in the gap, it isensured that there is no continuous, full-surface contact between thetablet material and the particle envelope. This is an important aspectof the present invention in order to ensure that the protective envelopearound the particle core is not damaged during the production processand also to minimize possible interactions between the tablet materialand said envelope, both with the aim of keeping the envelope reliablystable up to the clear rinsing cycle.

For fixing the particle in the cavity it is obviously not only possibleto use a conventional additive, but also other compositions and agentsfulfilling the same function, e.g. a mechanical fixing, such as e.g. anadequate frictional engagement between tablet and particle at at leastsome points or a plug connection between tablet and particle. It is alsopossible to use as fixing agents between particle and tablet furthercompounds which preferably melt or dissolve during the main cleaningcycle.

Obviously for the design of the cavity in the tablet or the particlereceived therein the most varied further geometrical shapes arepossible, such as e.g. an ellipsoid, cylinder, etc. The design and sizeof the cavity in the tablet and the particle received therein need notcorrespond to one another. Thus, e.g. a cylindrical particle can bereceived in a spherical cavity. All possible further combinationpossibilities are conceivable within the scope of the present invention.It is also possible to fill the cavity with several smaller particlesinstead of a single particle.

FIG. 3 illustrates a second embodiment of the inventive composition onthe basis of a conventional two-layer tablet 1. In this case the upperhalf-tablet 3 comprises two parts, which make available both an adequatecavity 5 for receiving the particle 6 and also an opening towards thetablet side 7. Thus, in this case the particle 6 is not completelysurrounded by the basic composition of the tablet, so that it is visiblefrom the outside in the interior of the tablet 1. Here again theparticle can either be received loosely in the cavity 5 (provided thatthrough a corresponding choice of the size of the particle 6 on the onehand and the size of the opening of the cavity 5 to the tablet side 11ensures that the particle or particles cannot pass through the openingin the cavity) or are fixed in the interior of the cavity 5 bycorresponding agents, such as e.g. adhesives.

A third possible embodiment can be gathered from FIG. 4. The basis onthis occasion is a unitary structure tablet 1′, i.e. formed from asingle layer 2′ with a unitary composition and colour. By means of asuitable device a depression 4′ is formed in said layer 2′. Into saiddepression 4′ is introduced the particle 6′, which in this case, as thedepression here is open to such an extent towards the side 11′ of thetablet 1′ that it would be possible for the particle to drop out of thedepression without fixing, fixing takes place in the depression by meansof an adhesive 10′ or a fixing intermediate layer or mechanically (e.g.by frictional engagement). This principle can obviously also betransferred to multilayer tablets.

Here again the most varied geometrical configurations are possible.Thus, e.g. parallel to the side 11′, the depression can have asubstantially circular cross-section. However, a random number of othercross-sections is conceivable, e.g. a random polygon. The particle 6′received in the depression 4′, as in the embodiment according to FIG. 3,can assume any random shape (also independent of the shape of thedepression 4′), such as e.g. an ellipsoid, cylinder, parallelepiped,etc.

Consideration can also be given to fixing the particles 6′ in a cavity,open on both sides, in the tablet, such as in a cylindrical hole 4′passing through the tablet body 1′ and in which is fixed acorresponding, cylindrical particle 6′ having a core 8′ and an envelope9′ (FIGS. 5a and b).

Another possible embodiment can be gathered from FIG. 6, which isconstructed in the same way as the embodiment according to FIG. 4, i.e.a unitary tablet 1′, i.e. a single layer 2′ with unitary composition andcolour. However, in the present case the particle 6″ contains aplurality of cores 8″, instead of a single core (as in FIG. 4), all ofwhich are embedded in an envelope 9″. However, it is e.g. possible inthis embodiment to incorporate cores having different composition anddifferent shape (encapsulated material or solid cores) in a singleparticle 6″.

Both in the represented embodiments and in further conceivablealternatives, it is important that for the particle containing thesubstance or substances to be released in the clear rinsing cycle, atleast in the first phase of the main cleaning cycle, there is a localenvironment having an adequate ionic concentration or pH-value servingas a “trigger” for dissolving the envelope, i.e. in a phase in which, ascan be gathered from FIG. 1, the pH-value is still relatively low, i.e.briefly is in a range where there would be an increased solubility ofthe envelope. This ensures that the envelope has an adequate stabilityup to the clear rinsing cycle.

EXAMPLE 1 Core Production a. Core for a Particle for Controlled Releaseof a Clear Rinsing Agent in the Clear Rinsing Cycle

The core or cores of the particle or particles intended to evolve theiractivity only during the clear rinsing cycle must in the case of theindicated aim incorporate at least one substance acting as a clearrinsing agent. Advantageously in the present invention a slightlyfoaming, nonionic surfactant is used. Such surfactants are e.g. fattyalcohol ethoxylates, fatty alcohol ethoxylate/propoxylates,ethoxylate/propoxylate polymers, such as e.g. the products ofSynperonic® and Brij® range of ICI, the products from the Plurafac®,Pluronic® and Lutensol® range of BASF, the products from the Genapol®range of Clariant and the products from the Poly-tergent® range of Olin.

Other possible examples for such surfactants are alkyl polyglycosides,glucamides and alkyl pyrrolidones. It is obviously possible to use allother surfactants able to evolve the desired action as clear rinsingagents.

Most substances known for use as clear rinsing agents are liquids orwax-like solids. However, in the present invention, a decisive part isnot played by the aggregate state of the substance acting as the clearrinsing agent. If liquids are used they can be made available prior tothe application of the envelope as surfactant-containing capsules, suchas e.g. gelatin capsules or can be brought into an envelopable state byother appropriate measures. Solids can conventionally be directlyprovided with the envelope and the coating process may have to bematched to the corresponding substance.

For the purposes of the present invention melt mixtures have provedparticularly advantageous and supply solid surfactant particles with amelting point above 35° C., preferably between approximately 55 and 70°C.

The combinations given in table 1 of different polyethylene glycols withthe surfactants Synperonic® RA 30, a block ethylene oxide/propyleneoxide, bound to a C₁₃-C₁₅ alcohol (C₁₃/C₁₅O (EO)₆(PO)₃) were produced inthe form of melt mixtures as cylinders weighing approximately 0.25 g.Melting point determinations gave the values of table 1.

TABLE 1 PEG PEG PEG PEG RA 30 8000 10000 20000 350000 melting point Code[%] [%] [%] [%] [%] [° C.] C1 30 70 58-63 C2 40 60 57-60 A30 50 50 57-60A31 60 40 54-58 A30 50 50 57-60 C3 60 40 57-60 C4 65 35 55-59 A33 50 5059-65 C17 60 40 58-63 C18 70 30 57-64 A34 50 50 59-65 C15 60 40 58-66C16 70 30 57-64

Although all combinations are fundamentally suitable, in particular the50:50 mixture A33 revealed an excellent stability and was easy tohandle, particularly with a view to the subsequent coating process. Allsamples dissolved rapidly in water, so that in each case an optimumactivity as a clear rinsing agent is ensured.

The invention is obviously in no way restricted to the combinationsgiven in exemplified form. As stated, it is possible to use in thepresent invention any type of surfactant usable as a clear rinsingagent.

b. Core for a Particle for the Controlled Release of a Fragrance in theClear Rinsing Cycle

Bleach-containing, i.e. oxidizing dishwashing agent compositionssignificantly limit the use possibilities of fragrances usable in suchcompositions. The controlled release of a fragrance in the clear rinsingcycle would allow a much greater flexibility when using fragrances.

For the controlled release of a fragrance or fragrance composition inthe clear rinsing cycle, it is possible to produce a core for acorresponding inventive particle, in that a mixture of 50 wt. % meltedpolyethylene glycol, e.g. PET 8000, 25 wt. % fragrance or fragrancecomposition and 25 wt. % diethyl phthalate are cooled in a mould inorder to form an e.g. spherical particle weighing e.g. 0.75 g.

c. Core for a Particle for the Controlled Release of an AntibacterialComposition in the Clear Rinsing Cycle

The use of an inventive particle with a core or several coresincorporating an antibacterial composition in a tablet for use in adishwasher would make available the possibility of simultaneouslyreleasing two different compositions in the clear rinsing cycle, namelythe antibacterial composition from the core or cores of the particleaccording to the invention and the clear rinsing agent from theconventional charging device of the dishwasher.

For such a particle a corresponding core is produced in that a mixtureof 100% melted benzalkonium chloride (Barquat® MS-100) is cooled in amould in order to produce an e.g. spherical particle weighing e.g. 0.64g.

d. Core for a Particle for Controlled Release of Enzymes in the ClearRinsing Cycle

As proteases, which are conventionally used in dishwashing agentcompositions, are proved to degrade lipases and therefore can reducetheir activity, it would be desirable to incorporate such lipases intothe core or cores of a particle according to the invention, so that thelipases would only be released in controlled form in the clear rinsingcycle, which could permit an optimum efficiency of these enzymes.

For this purpose 0.4 g of a granular, lipolytic enzyme (e.g. Lipolase®100T (Novo)) can be added to a hard gelatin capsule with an e.g.rounded, cylindrical shape, e.g. of the type used for medicaments.

EXAMPLE 2 Screening Process for Enveloping Materials

As stated hereinbefore it is vital for the present invention that thematerial for enveloping the particle core or cores incorporates thesubstances evolving their function essentially in the clear rinsingcycle of the dishwasher has a solubility dependent on the concentrationof a specific, selected ion. In this way the envelope is substantiallyinsoluble in the main cleaning cycle and is made soluble and is detachedfrom the particle if the ionic concentration decreases during theintermediate rinsing cycle or cycles or the clear rinsing cycle.

It has been observed that the dilution resulting from the pumping out ofthe washing liquor and the inflow of fresh water during the differentrinsing cycles leads to the ionic concentration decreasing 20 to 200times between the end of the main cleaning cycle and the last rinsingcycle.

On the basis of this observation processes for screening the suitabilityof different polymers for their use as enveloping materials have beendeveloped consisting of determining the solubility of such polymers attwo different ionic concentrations, which differ by at least 20 timesand preferably by 200 times.

The values for the ionic concentration, to be used during the screeningof the polymers, are dependent on the formulation of the basiccomposition of the tablet into which the enveloped particle is to beincorporated.

In fact, the value for the highest ionic concentration to be used forthe screening process corresponds to the concentration of the selectedion encountered in the washing liquor, after the machine dishwashingagent has completely dissolved. Once this concentration has beendetermined, the lower value for the ionic concentration should be fixedat 20 to 200 times below said higher value.

With these details it falls within the routine capacity of an expert inthis field to determine the values for the ionic concentration of thetest solutions to be used in the different test methods describedhereinafter.

Process for the Preparation of the Test Solution and Performing andEvaluating the Test

The materials to be investigated are dissolved in solvents in which theyare readily soluble. The solutions are spread over glass plates, thendried at ambient temperature until a constant weight occurs.

The glass plates are added at a controlled temperature to a beaker withtest solution. The solution is then stirred with a magnetic stirrer at acontrolled stirring speed. After about 10 minutes the glass plates areremoved from the beaker and dried at ambient temperature to constantweight. The results are expressed as weight loss (%).

Obviously the screening processes must be adapted to the composition ofthe machine dishwashing agent, because they exert a significantinfluence on the ionic concentration or pH-profile in the dishwashingcycle. The aim is in each case to check the degree of solubility of thecorresponding materials under different states, namely high or low ionicconcentration or pH-value.

With this information an average capacity only is required on the partof the expert to draw up specific test parameters for screening. Forexample, hereinafter two screening processes are described enabling thetesting of some of the possible materials for the envelope of theparticle according to the invention.

Screening Process 1

Screening process 1 was performed with buffer solutions as the mediumfor simulating the washing liquor. To this end two buffer solutions wereprepared in the following way:

Stock solution: 7.507 g glycine buffer (Merck 104169) 5.850 g NaCltopped up with water to 1000 ml pH 8 buffer 500 ml stock solutionsolution: 500 ml distilled H₂O 1 .23 g of 1 N NaOH pH 10 buffer 500 mlstock solution solution: 500 ml distilled H₂O 32.6 g of 1 N NaOH.

Screening Process 2

Screening process 2 was performed with the following cleaning agentformulation in order to simulate the conditions in different stages of adishwasher cycle. Concentrations of 4 to 5 g/l are of a conventionalnature for the cleaning agent load in the washing cycle. Concentrationsof approximately 20 to 40 mg/l are of a conventional nature for theclear rinsing cycle.

Cleaning Agent Formulation

Ingredient wt. % Sodium perborate monohydrate 9.00 Sodiumtripolyphosphate 48.00 Sodium carbonate 28.00 Polyethylene glycol 4.00Polymer 1.50 TAED 3.00 Enzyme 1.50 Surfactant 3.50 Additive 1.50 Total100.00

Screening Process 3

Screening process 3 is used for screening compounds, whose solubilitychanges as a function of the concentration of potassium ions. Thecompounds discovered with such a screening process can be used if in themain cleaning cycle, as stated hereinbefore, there is a correspondinglyhigh potassium ion concentration, which must be correspondingly reducedby dilution in the clear rinsing cycle.

Screening process 3 was performed with the following formulation tosimulate corresponding conditions.

Formulation

Ingredient wt. % Potassium tripolyphosphate 13.6 Potassium bicarbonate34.0 Potassium sulphate 23.1 Potassium chloride 12.4 Potassium carbonate9.7 Boric acid 2.0 Sodium perborate monohydrate 2.0 TAED 1.0 Paraffin1.0 Protease 0.2

EXAMPLE 3 Selection of Materials for the Particle Envelope

Using the screening processes described in example 2 different materialswere tested for their suitability as an envelope for the particleaccording to the present invention. One of these materials, hereinaftercalled “polymer 1” is a polymer such as is described in Japanese patentapplication KORAI 61-28440, i.e. having the general formula II withl/(l+m+n)=0.35; m/(l+m+n)=1500-1800.

The polymer was produced in the conventional manner by bulkpolymerization. The screening test results were as follows:

Screening Process 1

Films of polymer 1 were produced from a 10% solution in isopropanol.

pH-value of buffer weight loss at 30° C. weight loss at 60° C. solution[%]U [%] 10 7-8 5-8 8 81-88 91-95

Screening Process 2

Films of polymer 1 were produced from a 10% solution in a mixture ofwater and 1 N HCl (17:1).

Weight loss at 30° C. Weight loss at 60° C. Detergent conc. pH-value [%][%]   4 g/l  8-15  6-15 10.6 0.02 g/l 90-95 89-95  8.5

The invention is obviously not restricted to this exemplified polymerand naturally a wide variation possibility exists with respect to thepolymers referred to in Japanese patent applications KOKAI 60-141705,61-28440, 61-28441, 61-28596, 61-28597 and 61-28598 and can be extendedto compounds of formula IV:

in which R₁, independently of one another, is hydrogen or an alkyl groupwith 1 to 3 carbon atoms, R₂, independently of one another, is hydrogenor an alkyl group with 1 to 5 carbon atoms and x is an integer from 1 to6.

In addition, within the larger class of compounds according to formulaIII:

in which G is a linking group selected from —COO—, —OCO—, —CONH—, NHCO—,—NHCONH—, —NHCOO—, —OCONH— or —OCOO—, R₁, independently of one another,is hydrogen or an alkyl group with 1 to 5 carbon atoms and x is aninteger from 1 to 6, in exemplified manner polymers can be used having arepeat unit based on a compound of formula V:

e.g. a pH-sensitive polymer (“polymer 2”) with the repeat unit VI, whichis commercially obtainable from SANKYO under the trade name AEA®,

The above-described screening process 2 was also carried out withpolymer 2. 15 g of polymer 2 and 5 g of Mowiol® 3-98 (Clariant) weredissolved in 200 ml of a water/ethanol/1 N HCl 12:8:1 mixture. Filmswere formed and tested in the manner described hereinbefore and thefollowing results were obtained.

Weight loss at 30° C. Weight loss at 60° C. Detergent conc. pH-value [%][%]   4 g/l 2-8 5-7 10.6 0.02 g/l 32-40 45-47  8.5

Further polymers having the desired characteristics or which can beeasily modified in such a way that they are suitable for the purposes ofthe present invention are polymers of isomers or derivatives ofpyridine, preferably copolymers with styrene or acrylonitrile offormulas VII and VIII, in which G is a substituent at a random point ofthe pyridine ring.

A polymer according to formula VIII, namely poly(4-vinylpyridinestyrene) copolymer (Scientific Polymer Products, Inc.) “polymer 3” wastested according to screening process 2. 10 g of polymer 3 weredissolved in 230 ml of water/1 N HCl 6.25:1. The formation of the filmsand the performance of the tests were in the manner describedhereinbefore and the following results were obtained:

Weight loss at 30° C. Weight loss at 60° C. Detergent conc. pH-value [%][%]   4 g/l 0-6  5-12 10.6 0.02 g/l 68-85 92-94  8.5

Further polymers are (e.g. random) polymers derived from chitosan, basedon the following monomer units IX and X

It is also possible to use in the core material envelope substances orsubstance mixtures which, with regards to their solubility behaviour,react to a change in the ionic concentration, i.e. ionicconcentration-sensitive polymers. For this purpose it is e.g. possibleto use the partly hydrolyzed polyvinyl acetates (commercially availableunder the trade names Mowiol®-Clariant) described in EP 284 191 A2 andEP 284 334 A2, which reveal a corresponding ionic concentrationdependence in the presence of borates due to the complexing of theborates with polyols. Initial successful tests have been carried outwith Mowiol® 56-88.

Another ionic concentration-sensitive polymer is the polysaccharideK-carrageenan, which proved to be in screening process 3 (cf. example 2)a polymer whose solubility is dependent on the potassium ionconcentration in the surrounding medium. K-carrageenan is represented bythe following formula XI:

This polymer, called “polymer 4” was tested according to screeningprocess 3. 4 g of K-carrageenan were dissolved in 96 g of water. 10 g ofMowiol® 18-88 were dissolved in 90 g of water and both solutions weremixed. The resulting solution was used for forming films and performingtests in the manner described hereinbefore and the following resultswere obtained:

Detergent conc. Weight loss at 30° C. [%] Weight loss at 60° C. [%]   4g/l 0.5-3.0 11.0-12.0 0.02 g/l 24.5-25.0 78.0-85.0

The above list of compounds suitable for the envelope according to theinvention is obviously not exhaustive. Further polymers, which changetheir solubility by a modification of the pH-value or ionicconcentration in the desired range are conceivable or can be developedand are consequently covered by the protective scope of the presentinvention. The substances suitable for the envelope according to theinvention are not limited to polymeric compounds, although suchcompounds are preferred.

With the aid of the aforementioned screening process or processes, whichare adapted to the measurement of an ionic concentration sensitivity,further commercially available materials or those obtainable by easymodifications can be tested for their suitability in the presentinvention. The choice of such polymers is an easily solved problem forthe expert in view of the correspondingly clear aims and the indicatedscreening processes.

EXAMPLE 4 Production of a Particle According to the Invention

The different cores described in example 1 were used as a basis for theproduction of particles according to the invention. These cores wereindividually or in a plurality (FIG. 6) provided with an envelope in adevice for the application of a film coating of the type known in thepharmaceutical industry (e.g. obtainable from Lödiger, Hüttlin, GS,Manesty and Driam).

In the case where the core or cores have an ingredient revealing acertain incompatibility with the envelope material, prior to theapplication of said envelope the core or cores can be provided with aprotective coating. It is possible to use various prior art materialssuch as e.g. cellulose, cellulose derivatives, polyvinyl alcohol,polyvinyl alcohol derivatives and mixtures thereof. Although notprescribed, when using the cores of example 1 such a protective coatingwas used in all cases and use was made in preferred manner of a 10 wt. %aqueous solution of a polyvinyl alcohol, e.g. the polyvinyl alcoholMowiol® 5-88 (Clariant). The quantity of the protective coating appliedcan be varied by the expert as a function of the core composition andcorrespondingly adapted. Initial tests have revealed good results with 3wt. % in case 1 a, 2 wt. % in case 1 b, 3 wt. % in case 1 c and 4 wt. %in case 1 d of the polymer (dry weight), in each case based on theweight of the complete particle.

The ionic concentration-sensitive envelope can be applied to the core orcores or the protective coating in any random quantity and thickness,provided that it is ensured that the envelope is sufficiently rapidlydissolved or detached in the clear rinsing cycle to enable the substancecontained therein to evolve its action. In a preferred embodiment to thecores are applied 1 to 10 wt. %, preferably 4 to 8 wt. % of the ionicconcentration-sensitive enveloping material (dry weight), based on thetotal particle weight.

Preferably the size of the inventive particles should be such that theyare not or at least not significantly discharged from the dishwasherduring the pumping out processes following the main cleaning cycle orintermediate rinsing cycle. Generally a size of max diameter 1 cm isadequate. Larger or smaller dimensions can obviously be chosen, providedthat the appropriate operation overall is ensured.

For the further tests “polymer 1” of example 3 was used as the envelopeand applied as 10% solution of the polymer in 0.055 N aqueous HCl.

EXAMPLE 5 Production of a Two-layer Dishwashing Agent Tablet with ClearRinsing Agent Particles

A typical two-layer dishwashing agent tablet suitable for receiving aclear rinsing agent particle in the cavity formed therein in accordancewith the present invention, can be produced by moulding the pulverulentingredients in prior art machines and using operating parameters knownfrom the prior art. One possible tablet shape is a parallelepipedictablet formed from two substantially equally thick layers and in thelargest surface of each of these layers is formed a hemisphericalrecess, so that on joining together the two half-tablets a substantiallyspherical cavity is formed in the interior (cf. FIG. 2).

The composition of the dishwashing agent tablet is based on commerciallyavailable products. An exemplified composition can be gathered fromtable 2. It is obviously possible to use other compositions,particularly those optimized for supporting the compound surrounding thecore (e.g. in the provision of alkalinity).

TABLE 2 White layer Coloured layer 50% 50% Sodium perborate monohydrate18.00 Sodium tripolyphosphate 48.00 48.00 Sodium carbonate 24.00 32.00Polyethylene glycol 6000 3.00 5.00 Polymer 3.00 TAED 6.00 Enzyme 3.00Dye 0.02 Surfactant 4.50 2.50 Additive 2.50 0.50 100.00 100.00

For the tests performed in examples 6 and 7 half-tablets weighingapproximately 11.5 g were produced. The cavity resulting from thejoining of the half-tablets had an internal diameter of approximately1.2 cm.

The clear rinsing agent particle produced according to examples 1a and 4is placed in a hemispherical recess of the white or colouredhalf-tablet. Subsequently a fixing substance, e.g. an adhesive (e.g.polyethylene glycol, polyvinyl ether, polyvinyl alcohol, silicate,preferably melted PEG 4000) is applied to the corresponding half-tabletsurface and optionally the clear rinsing agent particle and the secondhalf-tablet (coloured or white) is pressed onto the first half-tabletwith clear rinsing agent particle.

EXAMPLE 6

This example describes a test proving the transfer of the clear rinsingagent surfactant into the clear rinsing cycle using the tablet producedaccording to example 5.

The clear rinsing agent particles have an average surfactant orpolyethylene glycol content of in each case approximately 0.37 g. Theaverage water quantity in the clear rinsing cycle is approximately 5liters. The expected maximum quantity of surfactant plus PEG in theclear rinsing cycle should therefore be 0.148 g/l when using one tabletper rinsing cycle.

In each case three different tests were performed with three differenttablets in a BOSCH SMS 3047 dishwasher. The water hardness wasapproximately 17° dH.

1. Dishwashing agent tablet without clear rinsing agent particles;temperature 65° C.

2. Dishwashing agent tablet with clear rinsing agent particles (example6); temperature 65° C.

3. Dishwashing agent tablet with clear rinsing agent particles (example6); temperature 55° C.

In each test a minimum of 1 liter of washing liquor was removed from theclear rinsing cycle shortly before the water was drained. The sampleswere designated 1.1 to 3.3. The liquor was then analyzed in order todetect the total quantity of surfactant plus polyethylene glycol in theclear rinsing cycle. The measurements were performed in that thesurfactant and PEG were extracted, the solvent evaporated and agravimetric determination of the nonvolatile residue was performed.

It is pointed out that with this analytical method both the nonionicsurfactant and the polyethylene glycol can be established.

TABLE 3 Test 1 (n = 1) Test 2 (n = 2) Test 3 (n = 3) mg/l % mg/l % mg/l% n.1 1.0 43.6 29.5 91.9 62.1 n.2 10.4 48.8 33.0 64.2 43.4 n.3 7.0 32.722.1 76.5 51.7

EXAMPLE 7

The test described in this example is used for testing the compositionaccording to the invention for effectiveness in the clear rinsing cycle.

For comparison with the inventively produced dishwashing agent tabletwith clear rinsing agent particles, as produced in example 6, the clearrinsing efficiency of separately added dishwashing agent and clearrinsing agent was investigated. The dishwashing agent corresponded tothe composition of the tablet according to the invention and acommercial clear rinsing agent was used. A BOSCH SMS 3047 dishwasher wasused. The water hardness was approximately 17 to 19° dH. The temperaturewas 65° C. The dishwasher was loaded with 20 glasses, 20 black porcelainplates and 20 cutlery items.

The dirtying of the dishwasher load was carried out in the followingway. 50 g of minced meat (pork:beef 1:1) were roast with 2 g of fat.After reaching a slightly brownish colour, to the meat was added a gravycontaining 100 ml of water, 1 g of gravy binder and 2.5 g of instantgravy.

This material was added to the dishwasher, the screen being closed by aplug in order to have the dirtying action in the machine up to the endof the washing program. The dishwashing agent wqs fed in at the start ofthe clear rinsing cycle. The dishwasher load was evaluated 10 minutesafter the end of the dish rinsing cycle.

Visual evaluation was based on the following:

4 points=no marks

3 points=1 to 4 marks

2 points=more than 4 marks up to ¼ of the surface covered with marks

1 point=¼ to ½ the surface covered with marks

0 point=almost completely covered with marks.

The mark or spot prevention efficiency is expressed as a percentage,100% efficiency representing the maximum number of 228 points. Theresults are given in table 4.

TABLE 4 Efficiency Cleaning agent + Cleaning agent + Tablet with clear 2ml of clear 3 ml of clear rinsing agent rinsing agent rinsing agentparticles Porcelain 66.9 75.6 96.9 Glass 25.6 26.9 49.4 Cutlery 80.690.6 78.8 Total 57.7 64.4 75.0

The results reveal an excellent clear rinsing agent of the compositionaccording to the invention. This was particularly marked with porcelainand glass, the efficiency in the case of table cutlery being comparablewith that of conventional compositions. Surprisingly there was in partsuperior clear rinsing efficiency of the inventive composition comparedwith the conventional procedure of separately adding dishwashing agentand clear rinsing agent.

The features of the invention disclosed in the above description, theclaims and the drawings can be essential to the implementation of theinvention in its different embodiments, both singly and in randomcombination.

What is claimed is:
 1. A composition for use in a dishwashing machine,comprising a tablet composition including a basic ion, the tabletperforming its function in a main cleaning cycle of the dishwashingmachine, a particle having a core and incorporating a componentperforming its function during a rinsing cycle of the dishwashingmachine, and an envelope surrounding the core and comprising a compoundwhose solubility is inversely proportional to a concentration of thebasic ion in a medium surrounding the particle, wherein the particle isarranged in or on the tablet such that only a portion of a surface ofthe particle directly contacts the tablet, and wherein the concentrationof the basic ion caused by dissolution of the tablet in the maincleaning cycle is sufficiently high to prevent dissolution of theenvelope or separation of the envelope from the particle core.
 2. Thecomposition according to claim 1, wherein the particle is received in acavity of the tablet and wherein the cavity encloses the particle andhas a larger volume than the particle received therein.
 3. Thecomposition according to claim 2, wherein the particle is looselyarranged in an interior of the cavity.
 4. The composition according toclaim 2, wherein the particle is fixed in an interior of the cavity. 5.The composition according to claim 4, wherein the particle is fixed byan adhesive.
 6. The composition according to claim 2, wherein the cavityis centrally arranged in an interior of the tablet.
 7. The compositionaccording to claim 6, wherein the cavity is spherical.
 8. Thecomposition according to claim 3, wherein the cavity is centrallyarranged in the interior of the tablet.
 9. The composition according toclaim 1, wherein the particle is received in a cavity of the tablet andwherein the cavity only partly surrounds the particle.
 10. Thecomposition according to claim 9, wherein the cavity is a depression ina surface of the tablet.
 11. The composition according to claim 9,wherein the particle is so received in the cavity that it does notproject beyond a surface of the tablet.
 12. The composition according toclaim 9, wherein the cavity has a substantially circular mouth.
 13. Thecomposition according to claim 12, wherein the mouth of the cavity issmaller than a diameter of the particle received therein.
 14. Thecomposition according to claim 9, wherein the particle is looselyarranged in the cavity.
 15. The composition according to claim 9,wherein the particle is fixed in the cavity.
 16. The compositionaccording to claim 15, wherein the particle is fixed with an adhesive.17. The composition according to claim 1, wherein the tablet comprises acomposition selected from the group consisting of a machine dishwashingagent composition, a water softener composition, a washing intensifiercomposition, and combinations thereof.
 18. The composition according toclaim 1, wherein the envelope comprises a compound which is soluble in amedium of a clear rinsing cycle such that it becomes dissolved ordetached from the particle core to allow release of a material of thecore into the medium of the clear rinsing cycle.
 19. The compositionaccording to claim 18, wherein a solubility of the compound is inverselyproportional to hydroxide ion concentration in the surrounding medium.20. The composition according to claim 19, wherein at a pH-value above10 the compound has no or only slight solubility and at a pH-value below9 the solubility is such that the compound becomes dissolved or detachedfrom the particle core.
 21. The composition according to claim 18,wherein the compound comprises a polymer.
 22. The composition accordingto claim 21, wherein the compound comprises a pH-sensitive polymercomprising a repeat unit, which has a basic function separate from abackbone chain of the polymer.
 23. The composition according to claim22, wherein the repeat unit is based on a compound selected from thegroup consisting of vinyl alcohol derivatives, acrylates and alkylacrylates having the basic function.
 24. The composition according toclaim 22, wherein the polymer is a carbohydrate functionalized with thebasic function.
 25. The composition according to claim 22, wherein thebasic function is an amine.
 26. The composition according to claim 25,wherein the amine is a secondary or tertiary amine.
 27. The compositionaccording to claim 25, wherein the repeat unit of the polymer is basedon a compound of formula III:

in which G is a linking group selected from—COO—,—OCO—,—CONH—,—NHCO—,NHCONH—, —NHCOO—, —OCONH— or —OCOO—, each R₁is, independently, hydrogen or an alkyl group with 1 to 3 carbon atoms,each R₂ is, independently, hydrogen or an alkyl group with 1 to 5 carbonatoms, and x is an integer from 1 to
 6. 28. The composition according toclaim 27, wherein the repeat unit is based on a compound of formula IV:

in which R₁ is hydrogen or an alkyl group with 1 to 3 carbon atoms, eachR₂ is, independently, hydrogen or an alkyl group with 1 to 5 carbonatoms, and x is an integer from 1 to
 6. 29. The composition according toclaim 22, wherein the basic function is an imine.
 30. The compositionaccording to claim 22, wherein the basic function is a basic aromaticN-containing group.
 31. The composition according to claim 30, whereinthe basic function is a pyridine group.
 32. The composition according toclaim 30, wherein the basic function is an imidazole group.
 33. Thecomposition according to claim 24, wherein the polymer is derived fromchitosan.
 34. The composition according to claim 18, wherein thecompound comprises k-carrageenan.
 35. The composition according to claim1, wherein the core comprises a material selected from the groupconsisting of surfactants, antibacterial compositions, silver protectionagents, fragrances, bleaches, disinfectants, odor masking agents,anti-coating agents, enzymes and combinations thereof.
 36. Thecomposition according to claim 35, wherein a portion of the corecomprises an encapsulated liquid.
 37. The composition according to claim36, wherein the encapsulated liquid is contained in a gelatin capsule.38. The composition according to claim 35, wherein the core is in solidform.
 39. The composition according to claim 1, wherein a portion of thecore has a melting point higher than 35° C.
 40. The compositionaccording to claim 39, wherein a portion of the core has a melting pointbetween 55° and 70° C.
 41. A process for washing dishes in a dishwashingmachine, comprising introducing into the dishwashing machine acomposition comprising a tablet composition including a basic ion, thetablet performing its function in a main cleaning cycle of thedishwashing machine, a particle having a core and incorporating acomponent performing its function during a clear rinsing cycle of thedishwashing machine, and an envelope surrounding the core and comprisinga compound whose solubility is inversely proportional to a concentrationof the basic ion in a medium surrounding the particle, wherein theparticle is arranged in or on the tablet such that only a portion of asurface of the particle contacts the tablet, and wherein theconcentration of the basic ion caused by dissolution of the tablet inthe main cleaning cycle is sufficiently high to prevent dissolution ofthe envelope or separation of the envelope from the particle core. 42.The process according to claim 41, further comprising a step ofintroducing into the dishwashing machine an additional dishwashingagent.